How to iterate odd and even runs alternatively?

Question

Bee 2016-4-29

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/281605-how-to-iterate-odd-and-even-runs-alternatively

评论： Elias Gule 2016-5-9

Hello there! I am trying to alternate between odd and even runs to do different things inside a for loop, i.e. the odd and even runs will be interdependent. For example: at t = 1, x1 = 10; at t = 2, x2 = x1+m; at t = 3, x1 = x2 ( derived from t = 2) +n and so on. The odd values of t indicate a local phase, for example and the even values of t indicate a global phase. I am trying to do this in the following way, but was wondering if there is a more efficient way to do this. Thanks for your time :)

while t < 1000
  if mod(t,2)
     % big block of code to calculate x using y
  else 
     % big block of code to calculate y using x
  end
end

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Roger Stafford 2016-4-29

在 MATLAB Online 中打开

You could also use a for-loop:

   for k = 1:2:999
     t = k; 
     Do block calculating x using y with t
     t = k+1;
     Do block calculating y using x with t
   end

You don't have waste time doing 'if' tests that way.

Bee 2016-5-4

编辑：Stephen23 2016-5-4

Hey Roger! This thing didn't come to my mind at all! It works perfectly for my purpose - simple and precise. Thanks a lot.

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Answer 1

Elias Gule 2016-4-29

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/281605-how-to-iterate-odd-and-even-runs-alternatively#answer_219981

在 MATLAB Online 中打开

Let's try. Define variables needed for calculation.

x = [NaN,NaN];
t = 1;
m = 2; % any value you like.
n = -2; % any value you like.

Begin processing.

while t < 100
  if mod(t,2)
    if t == 1
      x(1) = 10;
    else
      x(1) = x(2) + n;
    end
  else
     x(2) = x(1) + m;
  end  
  t = t + 1;
end

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Bee 2016-5-4

Hello Elias! Thanks a lot for your suggestion, but I was looking for a simpler and precise implementation like Roger suggested above. I am too lazy to type ;)

Elias Gule 2016-5-9